iBGP peers not exchanging routes

RouterOS Forwarding Protocols
1

Hi,

I'm trying to configure simple iBGP peering between two RouterOS 7.20.4 routers in the same AS (no route reflector hierarchy
needed), but routes are not being exchanged. I've noticed some unexpected cluster-id behavior.

Configuration:

  • Both routers in AS 4200000128
  • BGP instances configured WITHOUT cluster-id parameter
  • Connections set to local.role=ibgp
  • Both routers have output.redistribute=connected and filters configured
  • BGP session is established successfully

Observations:

  1. When I configure the BGP instance without cluster-id, the BGP session shows auto-generated cluster-ids (derived from
    router-id). For example:
    • Router A: .cluster-id=192.168.135.9
    • Router B: .cluster-id=192.168.128.3
  2. Both routers show prefix-count=0, even though advertisements show routes are being prepared
  3. When both instances have the same cluster-id configured, routes still aren't exchanged (both acting as RRs in the same cluster?)
  4. Switching to eBGP with different AS numbers works immediately

Questions:

  1. Is it expected that cluster-id is auto-generated from router-id even when not configured in the BGP instance?
  2. For simple iBGP peering between two equal routers (no RR hierarchy), what is the correct configuration to prevent both
    routers from acting as route reflectors?
  3. Is there a parameter on the BGP connection or template to specify "this is a regular iBGP peer, not a route reflector
    client"?
  4. Should I be using BGP templates to control this behavior?

Any guidance would be appreciated!

2

Hi,

could you please share yor iBGP configuration?

/routing/bgp/export

I have rr configuration as I specified ibgp-rr for role. You wanr just ibgp

add afi=ip as=655XX connect=yes disabled=no hold-time=10m input.filter=bgp-rule-in keepalive-time=30s listen=yes local.address=10.129.XX.XX .role=ibgp-rr name=BGP output.default-originate=never .filter-chain=bgp-rule-out .network=BGP_NET_OUT .redistribute=bgp remote.address=10.129.XX.XX .as=655XX router-id=10.129.XX.XX routing-table=main use-bfd=yes

image
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3

Hi,

i looked into that today and it works as expected i think my fault was to use the cluster-id.
Here the working config:
```
/routing bgp instance
add as=4200000003 disabled=no name=mam-hh-bb router-id=192.168.128.3 routing-table=main vrf=main
/routing bgp connection
add afi=ip,ipv6 as=4200000003 disabled=no instance=mam-hh-bb local.role=ibgp-rr name=mam-hh-test output.filter-chain=bgp-out .redistribute=connected remote.address=192.168.135.9 routing-table=main vrf=
main
add afi=ip,ipv6 as=4200000003 disabled=no instance=mam-hh-bb local.role=ibgp-rr name=mam-hh-gwx86 output.filter-chain=bgp-out .redistribute=connected remote.address=192.168.128.2 routing-table=main
vrf=main
add afi=ip,ipv6 as=4200000003 disabled=no instance=mam-hh-bb local.role=ibgp-rr name=gw-to-earth-ng output.filter-chain=bgp-out .redistribute=connected remote.address=192.168.129.88 routing-table=main
vrf=main
/routing filter rule
add chain=bgp-out rule=accept
add chain=bgp-in rule=accept
```
have to refine the filter a bit:)

Thx for coming back to me.

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